Robot system and robot control device

This disclosure relates to a robot system and a robot control device.

The introduction of autonomous control robots is progressing, and there is a need to expand the scope of the application.

Patent Literature 1 discloses a multi-robot system including a plurality of robots, a monitoring system that monitors operations of the robots, and an overall controller that operates the multi-robot, and operates cooperatively to achieve a specific purpose as a whole. The overall controller instructs, based on states of the robots and monitored positions and directions, the robots to operate, instructs the robots to correct the positions and the directions, and instructs the robots to operate upon the occurrence (or prediction) of an abnormality via a wireless LAN in real time.

Patent Literature 2 discloses that, in order to control an operation of a robot to obtain high work efficiency while securing safety of a worker, a trajectory correction unit of a robot control device sets, as an instructed trajectory, a corrected trajectory candidate selected based on time to reach a target position and a possibility of collision when it is determined that it is necessary to correct a trajectory, and sets, as an instructed trajectory, a trajectory from a current position toward a target position when it is determined that it is not necessary to correct the trajectory.

Japanese Unexamined Patent Application Publication No. 2006-954

Japanese Unexamined Patent Application Publication No. 2019-206080

In control of a plurality of robots that perform a cooperative operation, it is required not only to improve efficiency but also secure safety.

For example, in a case where a plurality of robots perform a cooperative operation at a location where a worker (human) comes and goes and where a safety fence is not present, when the worker enters a trajectory of the robots, and one of the robots performs change of the trajectory, for example, of such as an emergency stop, a failure may occur, for example, a conveyance target object gripped by the robot together with another robot may drop or may be damaged, or the robot may fall.

The multi-robot system described in Patent Literature 1 has a function of correcting a part of formation and securing a region for a robot in an abnormal state to be recovered when the robot is in the abnormal state and interference with another robot is predicted during the recovery operation. However, it does not describe transmission of correction data that requests another robot to cooperate.

The robot control device described in Patent Literature 2 is configured to estimate a possibility that a single robot collides with a worker (human). Therefore, it does not describe transmission of correction data that requests another robot to cooperate in a case where a plurality of robots are controlled.

An object of the present disclosure is to prevent a failure from occurring when a robot's operation is suddenly changed due to a disturbance or the like in a case where a plurality of robots perform a cooperative operation.

A robot system of this disclosure includes: a first robot; a second robot; a first robot control device that controls the first robot; a second robot control device that controls the second robot; and a sensor, the first robot and the second robot performing a cooperative operation. In the robot system, the first robot control device includes: a first trajectory planning unit that plans an operation of the first robot; a first control unit that performs the planned operation of the first robot; a first collision prediction unit that predicts, based on information of the sensor, collision of the first robot or the second robot with a disturbance; and a first interlocking stop unit, and the second robot control device includes: a second trajectory planning unit that plans an operation of the second robot; a second control unit that performs the planned operation of the second robot; a second collision prediction unit that predicts, based on information of the sensor, the collision of the first robot or the second robot with the disturbance; and a second interlocking unit. When the first collision prediction unit predicts the collision with the disturbance, the first interlocking stop unit generates a disturbance avoidance trajectory of the first robot and transmits the disturbance avoidance trajectory to the second interlocking stop unit, and the first robot and the second robot perform an operation of avoiding the disturbance.

According to the present disclosure, it is possible to prevent a failure from occurring when a robot's operation is suddenly changed due to a disturbance or the like in a case where a plurality of robots perform a cooperative operation.

A robot system and a robot control device used for the robot system according to the present disclosure can be applied to construction machinery, in-factory logistics, production equipment assembly, and the like.

Hereinafter, embodiments of the invention will now be described with reference to the drawings.

1 FIG. is a schematic configuration diagram illustrating a robot system according to a first embodiment.

100 110 110 120 110 120 110 130 In the drawing, the robot systemincludes a first robotA, a second robotB, a robot control deviceA (first robot control device) that controls the first robotA, a robot control deviceB (second robot control device) that controls the second robotB, and a sensor.

130 110 110 130 110 110 The sensoris installed separately from the first robotA and the second robotB. For example, the sensoris a camera or the like installed on a ceiling, a wall, or the like in a room in which the first robotA and the second robotB perform an operation.

110 110 140 110 110 140 110 110 The first robotA and the second robotB cooperate with each other to move a conveyance target object. In this case, the first robotA and the second robotB grip both end portions and the like of the conveyance target objectby gripping portions of the robots. Each of the first robotA and the second robotB has a manipulator having a joint portion. The gripping portions can be moved by the manipulators.

120 120 120 120 130 The robot control deviceA and the robot control deviceB are configured to be able to transmit and receive data and the like to and from each other. In addition, the robot control deviceA and the robot control deviceB can receive data or the like obtained by the sensor.

Although the drawing illustrates a case where the robot control devices are disposed outside the robots, the robot control devices may be disposed in the robots.

Each of the robot control devices includes an input unit, an output unit, an arithmetic unit, and a storage unit. The arithmetic units are central processing units (CPUs) or the like of computers. The storage units may include a database.

2 FIG. is a configuration diagram illustrating robot control devices according to the first embodiment.

120 220 230 240 250 120 220 230 240 250 As illustrated in the drawing, the robot control deviceA includes a trajectory planning unitA (first trajectory planning unit), a control unitA (first control unit), a collision prediction unitA (first collision prediction unit), and an interlocking stop unitA (first interlocking stop unit). Similarly, the robot control deviceB includes a trajectory planning unitB (second trajectory planning unit), a control unitB (second control unit), a collision prediction unitB (second collision prediction unit), and an interlocking stop unitB (second interlocking stop unit).

220 220 210 220 110 230 230 110 220 110 230 230 110 The trajectory planning unitsA andB receive a task command from a high-level controller. The trajectory planning unitA creates, based on the task command, a program or the like regarding an operation of the first robotA, and transmits the program or the like to the control unitA. The control unitA controls an operation of the first robotA based on the program or the like. Similarly, the trajectory planning unitB creates, based on the task command, a program or the like regarding an operation of the second robotB, and transmits the program or the like to the control unitB. The control unitB controls an operation of the second robotB based on the program or the like.

220 220 The trajectory planning unitsA andB may autonomously create the programs or the like as described above and prepare and store the programs or the like in advance.

240 230 110 110 110 110 240 230 110 110 110 110 The collision prediction unitA receives the program or the like from the control unitA and receives information indicating actual operations of the first robotA and the second robotB, situations around the first robotA and the second robotB, a disturbance or the like such as approach of a human. Similarly, the collision prediction unitB receives the program or the like from the control unitB and receives information indicating the actual operations of the first robotA and the second robotB, the situations around the first robotA and the second robotB, the disturbance or the like such as the approach of the human.

240 240 110 110 240 250 240 250 250 110 250 110 Then, when the collision prediction unitsA andB determine that it is necessary to perform change, stop, or the like of trajectories of the first robotA and the second robotB, in order to avoid the disturbance or the like, the collision prediction unitA transmits the result of the determination to the interlocking stop unitA, and the collision prediction unitB transmits the result of the determination to the interlocking stop unitB. The interlocking stop unitA transmits a command of change, stop, or the like of the trajectory, to the first robotA in accordance with the result of the determination. Similarly, the interlocking stop unitB transmits a command of change, stop, or the like of the trajectory to the second robotB in accordance with the result of the determination.

110 110 140 140 1 FIG. The first robotA and the second robotB that have received the command cooperate with each other to avoid dropping of the conveyance target object(), damage to the conveyance target object, and the like, and perform operation of change, stop or the like of the trajectories.

3 FIG. 2 FIG. is a configuration diagram illustrating interlocking stop units illustrated in.

3 FIG. 250 310 320 330 250 310 320 330 310 310 As illustrated in, the interlocking stop unitA includes a hand stopping trajectory generation unitA, a joint angle stopping trajectory generation unitA, and a stopping trajectory control unitA. Similarly, the interlocking stop unitB includes a hand stopping trajectory generation unitB, a joint angle stopping trajectory generation unitB, and a stopping trajectory control unitB. The hand stopping trajectory generation unitA and the hand stopping trajectory generation unitB can transmit and receive data to and from each other. Joint angles are angles of the joints of the manipulators, and are adjusted by motors of the joints of the manipulators.

310 240 310 240 2 FIG. 2 FIG. The hand stopping trajectory generation unitA receives data such as the result of the determination from the collision prediction unitA (), and the hand stopping trajectory generation unitB receives data such as the result of the determination from the collision prediction unitB ().

4 FIG. is a flowchart illustrating a process by the interlocking stop units.

250 250 240 240 310 310 250 250 410 In the drawing, when any one of the interlocking stop unitsA andB receives the result of the determination, such as the change, stop, or the like of the trajectory of the robot, from the collision prediction unitA orB, the hand stopping trajectory generation unitA orB included in the interlocking stop unitA orB determines whether or not data or a program for a hand stopping trajectory is included in the result of the determination (step S).

310 310 420 In a case where the data or the program for the hand stopping trajectory is not included, the hand stopping trajectory generation unitA orB determines whether or not it is necessary to stop the hand (step S).

430 In a case where it is determined that it is necessary to stop the hand, the robot determines whether or not the robot is performing a cooperative operation (step S). In this case, the cooperative operation is an operation in which two or more robots simultaneously grip a single object or the like to convey the object, or the like. In other words, the cooperative operation includes supporting of the conveyance target object.

440 450 460 In a case where it is determined that the cooperative operation is being performed, a robot (partner) performing the cooperative operation is identified (step S). After that, the maximum acceleration of the identified robot is estimated (step S). Then, a trajectory for stopping a hand is generated based on the maximum acceleration (step S). In other words, a program for the trajectory for stopping the hand or the like is created.

140 A reason why the maximum acceleration of the partner robot is estimated is that, when it is not based on the maximum acceleration, the conveyance target objectmay drop or the robot may fall.

470 The program or the like is transmitted to the other robot that is performing the cooperative operation, or to the robot control devices (step S).

480 Next, each of the robots or each of the robot control devices uses the program or the like to generate a stopping trajectory for the joint angle (step S).

490 After that, control to stop the robots is performed (step S).

410 415 480 490 On the other hand, in a case where the data or the program for the hand stopping trajectory is included in step S, a trajectory for stopping the hand of the other robot following is generated based on the received hand stopping trajectory (step S). After that, the processing in steps Sand Sis performed.

430 435 480 490 In addition, in a case where it is determined that the cooperative operation is not being performed in step S, a trajectory for stopping the hand of the robot is generated (step S). After that, the processing in steps Sand Sis performed.

5 FIG. is a configuration diagram illustrating means for calculating upper limits of velocities and of acceleration of arms in the interlocking stop units.

510 520 530 In the drawing, each of the interlocking stop units includes a storage devicehaving a database, an arm specification identification unit, and an arm velocity/acceleration upper limit calculation unit.

520 520 510 530 When the arm specification identification unitreceives a robot ID (a number or the like given to distinguish the robot), the arm specification identification unitidentifies, from the database of the storage device, specifications such as each axis motor, a link, and the like of the arm of the robot, the weight of the hand included in the arm, and the like. The identified information of the arm is transmitted to the arm velocity/acceleration upper limit calculation unit.

530 140 1 FIG. The arm velocity/acceleration upper limit calculation unituses the information, data of the weight of the work (conveyance target object()) gripped by the robot, and the like to calculate an upper limit of the velocity of the arm and an upper limit of the acceleration of the arm, and outputs the upper limits.

6 FIG. is a flowchart illustrating a stop process when a disturbance occurs.

240 601 610 250 620 310 110 310 630 140 In the drawing, in a case where the collision prediction unitA determines that a risk of collision with a disturbanceis high (step S), the interlocking stop unitA estimates the maximum value of acceleration of the robot (partner) performing a cooperative operation (step S). Then, the hand stopping trajectory generation unitA generates a trajectory for stopping the hand of the first robotA and transmits data of the trajectory to the hand stopping trajectory generation unitB (step S). It is desirable to slow down as quickly as possible. However, if the capacity of a motor or the like of the partner is not matched, the conveyance target objectmay drop or the robot may fall.

320 330 640 330 650 The joint angle stopping trajectory generation unitA uses data of the generated trajectory for stopping the hand to generate a command regarding the joint angle and transmits the command to the stopping trajectory control unitA (step S). The stopping trajectory control unitA performs control based on the trajectory for stopping the hand (step S).

310 110 635 Meanwhile, the hand stopping trajectory generation unitB that has received the data generates a trajectory for stopping the hand of the second robotB (step S).

320 330 645 330 655 The joint angle stopping trajectory generation unitB uses data of the generated trajectory for stopping the hand to generate a command regarding the joint angle and transmits the command to the stopping trajectory control unitB (step S). The stopping trajectory control unitB performs control based on the trajectory for stopping the hand (step S).

7 FIG. is a schematic diagram illustrating a state in which two robots operate cooperatively.

110 710 110 710 710 110 110 710 110 110 710 710 In the drawing, the hand of the first robotA moves as shown in a trajectoryA. Meanwhile, the hand of the second robotB moves along a trajectoryB having the same shape as that of the trajectoryA. This is implemented by the first robotA or the robot control device for the first robotA transmitting data of the trajectoryA to the second robotB or the robot control device for the second robotB. It is desirable that the data be point sequence data at each time point as indicated by the trajectoriesA andB. This is because, in the case of an emergency stop, the point sequence data can be processed within a shorter period.

8 FIG. is a flowchart illustrating a process by the interlocking stop units for an emergency stop.

4 FIG. In the drawing, in addition to the steps illustrated in, steps for an emergency stop are provided.

8 FIG. 810 That is, in, whether or not an emergency stop is required is determined first (step S).

810 815 825 835 845 In a case where it is determined that the emergency stop is required in step S, an emergency braking command is transmitted to a robot for which the determination has been made (step S). Then, whether or not a cooperative operation is being performed is determined (step S). When the cooperative operation is being performed, a robot performing the cooperative operation is identified (step S), and an emergency braking command is transmitted to the robot or the control device for the robot (step S). On the other hand, when the cooperative operation is not being performed, the process ends.

810 4 FIG. In a case where the emergency stop is not required in step S, the next processing is performed in a similar manner to the step illustrated in.

250 250 240 240 310 310 250 250 820 When any one of the interlocking stop unitsA andB receives, from the collision prediction unitA orB, the result of the determination such as a change or stop in the trajectory of the robot, the hand stopping trajectory generation unitA orB included in the interlocking stop unitA orB determines whether or not data or a program for the hand stopping trajectory is included in the result of the determination (step S).

310 310 830 In a case where the data or the program for the hand stopping trajectory is not included, the hand stopping trajectory generation unitA orB determines whether or not it is necessary to stop the hand (step S).

840 In a case where it is determined that it is necessary to stop the hand, it is determined whether or not the robot is performing a cooperative operation (step S).

850 860 870 In a case where it is determined that the cooperative operation is being performed, a robot performing the cooperative operation is identified (step S). Then, the maximum acceleration of the identified robot is estimated (step S). Then, a trajectory for stopping the hand is generated based on the maximum acceleration (step S). In other words, a program or the like for the trajectory for stopping the hand is created.

880 Then, the program or the like is transmitted to the other robot that is performing the cooperative operation or to the robot control device (step S).

890 Next, each of the robots or each of the robot control devices uses the program or the like to generate a stopping trajectory for the joint angle (step S).

900 After that, control to stop each of the robots is performed (step S).

820 822 890 900 On the other hand, in a case where the data or the program for the hand stopping trajectory is included in step S, a trajectory for stopping the hand of the other robot following is generated based on the received hand stopping trajectory (step S). After that, processing in step Sand Sis performed.

840 842 890 900 In addition, in a case where it is determined that the cooperative operation is not being performed in step S, a trajectory for stopping the hand of the robot is generated (step S). After that, the processing in step Sand Sis performed.

According to the present embodiment, from one of a plurality of robots that perform a cooperative operation, another robot can obtain information regarding a change in a trajectory such as a trajectory for stopping a hand, and the other robot can generate, based on the information, a trajectory for stopping a hand, and perform an operation of changing a trajectory, such as a stop operation while keeping a distance between the hands.

9 FIG. is a schematic configuration diagram illustrating a robot system according to a second embodiment.

901 910 910 920 910 920 910 In the drawing, the robot systemincludes a first robotA, a second robotB, a robot control deviceA that controls the first robotA, and a second robot control deviceB that controls the second robotB.

910 910 910 930 910 930 930 935 910 930 935 910 Each of the first robotA and the second robotB includes wheels (wheels for movement) and can move. The first robotA includes a sensorA. The second robotB includes a sensorB. The sensorA has a field of viewA and can monitor a direction of movement of the first robotA. The sensorB has a field of viewB and can monitor a direction of movement of the second robotB.

910 910 140 910 910 140 The first robotA and the second robotB cooperate with each other to move the conveyance target object. In this case, the first robotA and the second robotB grip both end portions and the like of the conveyance target object.

910 910 930 930 140 In other words, the first robotA and the second robotB move forward at a constant speed with the sensorsA andB at the front such that the conveyance target objectdoes not drop.

920 920 920 930 920 930 The robot control deviceA and the robot control deviceB are configured to be able to transmit and receive data to and from each other. In addition, the robot control deviceA can receive data obtained by the sensorA. The robot control deviceB can receive data obtained by the sensorB.

10 FIG. is a flowchart illustrating a stop process when a disturbance occurs.

3 FIG. The robots corresponding to the drawing includes the wheels and can move, and are connected to the robot control devices having the interlocking stop units illustrated in, like the robot control devices according to the first embodiment.

10 FIG. 240 1001 1010 240 1020 310 910 310 1030 In, in a case where the collision prediction unitA determines that a risk of collision with a disturbanceis high (step S), the collision prediction unitA estimates the maximum value of acceleration of the robot (partner) performing a cooperative operation (step S). Then, the hand stopping trajectory generation unitA generates a trajectory for stopping a hand of the first robotA and transmits data of the trajectory to the hand stopping trajectory generation unitB (step S).

320 330 1040 330 1050 The joint angle stopping trajectory generation unitA uses the data of the generated trajectory for stopping the hand, to generate a command regarding a joint angle and transmits the command to the stopping trajectory control unitA (step S). The stopping trajectory control unitA performs control based on the trajectory for stopping the hand (step S).

310 910 1035 On the other hand, the hand stopping trajectory generation unitB that has received the data generates a trajectory for stopping a hand of the second robotB (step S).

320 330 1045 330 1055 The joint angle stopping trajectory generation unitB uses the data of the generated trajectory for stopping the hand to generate a command regarding a joint angle and transmits the command to the stopping trajectory control unitB (step S). The stopping trajectory control unitB performs control based on the trajectory for stopping the hand (step S).

In the present embodiment, when a robot is moving, one of the interlocking stop units generates a trajectory for stopping the robot and transmits data of the trajectory for stopping to the other interlocking stop unit in order to stop the movement. The other robot can stop in conjunction.

It is desirable that a command regarding the wheels include point sequence data of a rotation speed, rotation acceleration, or rotation angle of the wheels for stopping.

11 FIG. is a schematic configuration diagram illustrating a robot system according to a third embodiment.

1101 1110 1110 1120 1110 1120 1110 In the drawing, the robot systemincludes a first robotA, a second robotB, a robot control deviceA that controls the first robotA, and a robot control deviceB that controls the second robotB.

1110 1110 1110 1130 1110 1130 1130 1135 1110 1130 1135 1110 Each of the first robotA and the second robotB includes wheels and can move. The first robotA includes a sensorA. The second robotB includes a sensorB. The sensorA has a field of viewA and can monitor a direction of movement of the first robotA. The sensorB has a field of viewB and can monitor a direction (backward) opposite to the direction of the movement of the second robotA.

1110 1110 140 1110 1110 140 The first robotA and the second robotB cooperate with each other to move the conveyance target object. In this case, the first robotA and the second robotB support a lower surface such as both end portions of the loaded conveyance target object. In the present embodiment, a cooperative operation is an operation in which two or more robots perform a conveyance operation or the like while simultaneously supporting a single object or the like on loading portions.

1110 1110 1130 1110 140 In other words, the first robotA and the second robotB move forward at a constant speed with the sensorA of the first robotA being at the front such that the conveyance target objectdoes not drop.

1120 1120 1120 1130 1120 1130 The robot control deviceA and the robot control deviceB are configured to be able to transmit and receive data to and from each other. In addition, the robot control deviceA can receive data or the like obtained by sensorA. The robot control deviceB can receive data or the like obtained by the sensorB.

12 FIG. is a flowchart illustrating a stop process when a disturbance occurs.

3 FIG. The robots corresponding to the drawing are connected to the robot control devices having the interlocking stop units illustrated in, as similar to the robot control device of Embodiment 1, except that the robots corresponding to this drawing have the loading portions without having hands (gripping portions) and have wheels and can move.

12 FIG. 240 1201 1210 240 1220 310 1110 1110 1230 In, in a case where the collision prediction unitA determines that a risk of collision with a disturbanceis high (step S), the collision prediction unitA estimates the maximum value of acceleration of the robot (partner) performing a cooperative operation (step S). Then, a loading portion stopping trajectory generation unit that has a function similar to that of the hand stopping trajectory generation unitA generates a trajectory for stopping the loading portion of the first robotA and transmits data of the trajectory to a loading portion stopping trajectory generation unit of the second robotB (step S).

320 330 1240 330 1250 A wheel stopping trajectory generation unit that has a function similar to that of the joint angle stopping trajectory generation unitA uses the data of the generated trajectory for stopping the loading portion, to generate a command regarding the wheels and transmits the command to the stopping trajectory control unitA (step S). The stopping trajectory control unitA performs control based on the trajectory for stopping the loading portion (step S). It is desirable that the command regarding the wheels includes point sequence data of a rotation speed, rotation acceleration, or a rotation angle of the wheels for stopping.

1110 1110 1235 Meanwhile, the loading portion stopping trajectory generation unit of the second robotB that has received the data generates a trajectory for stopping the loading portion of the second robotB (step S).

1110 330 1245 330 1255 The loading portion stopping trajectory generation unit of the second robotB uses the data of the generated trajectory for stopping the loading portion, to generate a command regarding the wheels and transmits the command to the stopping trajectory control unitB (step S). The stopping trajectory control unitB performs control based on the trajectory for stopping the loading portion (step S).

In the first to third embodiments, although the trajectory for stopping the hand or the loading portion is generated, the functions are common in that the conveyance target object is supported, and thus the hand and the loading portion are collectively referred to as a “supporting portion”. In addition, the operations of avoiding dropping of the conveyance target object, damage to the conveyance target object, and the like, and changing or stopping of a trajectory and the like, that is, the operations of avoiding a disturbance, are collectively referred to as a “disturbance avoidance operation”, and trajectories of the components accompanying the operation are collectively referred to as a “disturbance avoidance trajectory”.

100 : robot system 110 A: first robot 110 B: second robot 120 120 A,B: robot control device 130 : sensor 140 : conveyance target object 210 : high-level controller 220 220 A,B: trajectory planning unit 230 230 A,B: control unit 240 240 A,B: collision prediction unit 250 250 A,B: interlocking stop unit 310 310 A,B: hand stopping trajectory generation unit 320 320 A,B: joint angle stopping trajectory generation unit 330 330 A,B: stopping trajectory control unit 510 : storage device 520 : arm specification identification unit 530 : arm velocity/acceleration upper limit calculation unit 601 : disturbance